1. Field
Embodiments of the present invention relate to a solenoid valve control apparatus and method, capable of reducing operation noise of a solenoid valve.
2. Description of the Related Art
In a general vehicle equipped with an electronically controlled brake system, for example an ABS (Anti-lock Brake System), solenoid valves are mounted to inlet and outlet sides of four wheels, respectively.
When such an ABS vehicle begins to slide by braking force thereof exceeding friction force between the wheels of the vehicle and the road surface, the solenoid valves of the associated wheels operate to decrease pressure. When the vehicle begins to be driven again, operation by which the solenoid valves operate to apply pressure to the wheels is continuously generated. The vehicle is stably braked without sliding owing to such ABS operation.
Each of the solenoid valves supplies or blocks brake oil pressure from the electronically controlled brake system to a wheel cylinder.
The solenoid valve is opened and closed by current supplied to a solenoid coil therein.
An existing solenoid valve control apparatus includes a shunt resistance unit which detects current flowing in a solenoid coil within a solenoid valve, a switching unit which switches the current flowing in the solenoid coil, a pre-driver which outputs a driving signal to the switching unit so as to turn the switching unit on/off, and an ECU which monitors the current flowing in the solenoid coil through the shunt resistance unit and controls the switching unit through the pre-driver such that target current flows in the solenoid coil based on the monitored result.
In the related art, the ECU outputs a driving signal having a fixed frequency to the switching unit through the pre-driver while controlling current flowing in the solenoid coil such that the current reaches target current.
As a result, acoustic noise having the same frequency may be caused even in a solenoid valve assembly.